Polymerizable polydimethylsiloxane-polyoxyalkylene block copolymers

ABSTRACT

The invention provides a polymerizable polydimethylsiloxane-polyoxyalkylene block copolymer which comprises (1) a linear polymer chain comprising at least two polydimethylsiloxane segments, one hydrophilic polyoxyalkylene segment between each pair of polydimethylsiloxane segments, and one amide-rich linker between each pair of one polydimethylsiloxane segment and one hydrophilic polyoxyalkylene segment, and (2) two terminal (meth)acryloyl groups. The hydrophilized polydiorganosiloxane vinylic crosslinker has a weight average molecular weight of at least 3000 Daltons. The invention is also related to a silicone hydrogel contact lens produced from a polymerizable polydimethylsiloxane-polyoxyalkylene block copolymer of the invention.

This application claims the benefit under 35 USC § 119 (e) of U.S.provisional application No. 62/406,467 filed 11 Oct. 2016, hereinincorporated by reference in its entirety.

The present invention is related to a class ofdi-(meth)acryloyl-terminated polydimethylsiloxane-polyoxyalkylene blockcopolymers, lens formulations which comprise suchpolydimethylsiloxane-polyoxyalkylene block copolymers and are suitablefor making silicone hydrogel contact lenses. In addition, the presentinvention is related to silicone hydrogel contact lenses made from sucha lens formulation.

BACKGROUND

In recent years, soft silicone hydrogel contact lenses become more andmore popular because of their high oxygen permeability and comfort.“Soft” contact lenses can conform closely to the shape of the eye, sooxygen cannot easily circumvent the lens. Soft contact lenses must allowoxygen from the surrounding air (i.e., oxygen) to reach the corneabecause the cornea does not receive oxygen from the blood supply likeother tissue. If sufficient oxygen does not reach the cornea, cornealswelling occurs. Extended periods of oxygen deprivation cause theundesirable growth of blood vessels in the cornea. By having high oxygenpermeability, a silicone hydrogel contact lens allows sufficient oxygenpermeate through the lens to the cornea and to have minimal adverseeffects on corneal health.

One of lens forming materials widely used in making silicone hydrogelcontact lenses is a polydiorganosiloxane (e.g., polydimethylsiloxane)vinylic crosslinker which can provide high oxygen permeability toresultant contact lenses. But, a polydimethylsiloxane vinyliccrosslinker can affect the mechanical properties, e.g., elastic modulus,of the resultant contact lenses. For example, a low molecular weightpolydimethylsiloxane vinylic crosslinker (<2,000 g/mol) may provide aresultant contact lens with a relatively high elastic modulus in orderto achieve a desired oxygen permeability. A relative high molecularweight polydimethylsiloxane vinylic crosslinker is typically used inachieve both the high oxygen permeability and the low elastic modulus.However, because of its hydrophobic nature, a polydimethylsiloxanevinylic crosslinker, especially one with high molecular weight, is notcompatible with hydrophilic components in a lens formulation, including,e.g., N,N-dimethylacrylamide (DMA), N-vinylpyrrolidone (NVP),N-vinyl-N-methylacetamide (VMA), or an internal wetting agent. It wouldbe difficult to obtain homogeneous lens formulations (i.e., clear lensformulations) from use of such a polydimethylsiloxane vinyliccrosslinker.

It would be even more difficult to obtain a homogeneous, solventlesslens formulation from use of such a polydimethylsiloxane vinyliccrosslinker. Use of organic solvents in preparing silicone hydrogelcontact lens can be costly and is not environmentally friendly.

Therefore, there is a need for new hydophilized polydiorganosiloxanevinylic crosslinkers suitable for preparing a solventless lensformulation that can be used to produce silicone hydrogel contact lenseswith long thermal stability.

Documents, including U.S. Pat. Nos. 4,260,725, 5,034,461, 5,346,946,5,416,132, 5,449,729, 5,486,579, 5,512,205, 5,760,100, 5,994,488,6,858,218, 6,867,245, 7,671,156, 7,744,785, 8,129,442, 8,163,206,8,501,833, 8,513,325, 8,524,850, 8,835,525, 8,993,651, and 9,187,601 andU.S. Pat. App. Pub. No. 2016/0090432 A1, disclose that various lensformulations (which are either solvent-containing or solventlessformulations) comprising one or more hydrophilized polysiloxanecrosslinkers can be used for making silicone hydrogel contact lenses.

SUMMARY OF THE INVENTION

The present invention, in one aspect, provides a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer. The polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of the inventioncomprises: (1) a linear polymer chain comprising at least twopolydimethylsiloxane segments, one hydrophilic polyoxyalkylene segmentbetween each pair of polydimethylsiloxane segments, and one amide-richlinker between each pair of one polydimethylsiloxane segment and onehydrophilic polyoxyalkylene segment; (2) two terminal (meth)acryloylgroups, wherein the polydimethylsiloxane-polyoxyalkylene block copolymerhas a number-average molecular weight of at least 3000 Daltons.

In another aspect, the invention provides a silicone hydrogel contactlens comprising a crosslinked polymeric material comprising: units of apolymerizable polydimethylsiloxane-polyoxyalkylene block copolymer ofthe invention (described above), units of a siloxane-containing vinylicmonomer, units of at least one hydrophilic vinylic monomer, wherein thesilicone hydrogel contact lens, when being fully hydrated, has an oxygenpermeability (Dk) of at least about 70 barrers, a water content of fromabout 25% to about 70% by weight, and an elastic modulus of from about0.2 MPa to about 1.2 MPa.

In a further aspect, the present invention provides a method forproducing silicone hydrogel contact lenses. The method comprises thesteps of: preparing a lens-forming composition which is clear at roomtemperature and optionally but preferably at a temperature of from about0 to about 4° C., wherein the lens-forming composition comprises (a)from about 5% to about 35% by weight of a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of the invention,(b) a siloxane-containing vinylic monomer, (c) from about 30% to about60% by weight of at least one hydrophilic vinylic monomer, (d) at leastone free-radical initiator, provided that the above-listed polymerizablecomponents and any additional polymerizable components add up to 100% byweight; introducing the lens-forming composition into a mold, whereinthe mold has a first mold half with a first molding surface defining theanterior surface of a contact lens and a second mold half with a secondmolding surface defining the posterior surface of the contact lens,wherein said first and second mold halves are configured to receive eachother such that a cavity is formed between said first and second moldingsurfaces; curing thermally or actinically the lens-forming compositionin the lens mold to form a silicone hydrogel contact lens.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Generally, the nomenclatureused herein and the laboratory procedures are well known and commonlyemployed in the art. Conventional methods are used for these procedures,such as those provided in the art and various general references. Wherea term is provided in the singular, the inventors also contemplate theplural of that term. The nomenclature used herein and the laboratoryprocedures described below are those well known and commonly employed inthe art.

“About” as used herein in this application means that a number, which isreferred to as “about”, comprises the recited number plus or minus 1-10%of that recited number.

An “ophthalmic device”, as used herein, refers to a contact lens (hardor soft), an intraocular lens, a corneal onlay, other ophthalmic devices(e.g., stents, glaucoma shunt, or the like) used on or about the eye orocular vicinity.

“Contact Lens” refers to a structure that can be placed on or within awearer's eye. A contact lens can correct, improve, or alter a user'seyesight, but that need not be the case. A contact lens can be of anyappropriate material known in the art or later developed, and can be asoft lens, a hard lens, or a hybrid lens. A “silicone hydrogel contactlens” refers to a contact lens comprising a silicone hydrogel material.

A “hydrogel” or “hydrogel material” refers to a crosslinked polymericmaterial which is insoluble in water, but can absorb at least 10 percentby weight of water when it is fully hydrated.

A “silicone hydrogel” refers to a silicone-containing hydrogel obtainedby copolymerization of a polymerizable composition comprising at leastone silicone-containing vinylic monomer or at least onesilicone-containing vinylic macromer or at least oneactinically-crosslinkable silicone-containing prepolymer.

“Hydrophilic,” as used herein, describes a material or portion thereofthat will more readily associate with water than with lipids.

A “vinylic monomer” refers to a compound that has one sole ethylenicallyunsaturated group and is soluble in a solvent.

The term “soluble”, in reference to a compound or material in a solvent,means that the compound or material can be dissolved in the solvent togive a solution with a concentration of at least about 0.5% by weight atroom temperature (i.e., a temperature of about 20° C. to about 30° C.).

The term “insoluble”, in reference to a compound or material in asolvent, means that the compound or material can be dissolved in thesolvent to give a solution with a concentration of less than 0.005% byweight at room temperature (as defined above).

The term “olefinically unsaturated group” or “ethylenically unsaturatedgroup” is employed herein in a broad sense and is intended to encompassany groups containing at least one >C═C<group. Exemplary ethylenicallyunsaturated groups include without limitation (meth)acryloyl

in which R″ is hydrogen or methyl), allyl, vinyl, styrenyl, or other C═Ccontaining groups.

As used herein, “actinically” in reference to curing, crosslinking orpolymerizing of a polymerizable composition, a prepolymer or a materialmeans that the curing (e.g., crosslinked and/or polymerized) isperformed by actinic irradiation, such as, for example, UV irradiation,ionizing radiation (e.g. gamma ray or X-ray irradiation), microwaveirradiation, and the like. Thermal curing or actinic curing methods arewell-known to a person skilled in the art.

The term “(meth)acrylamide” refers to methacrylamide and/or acrylamide.

The term “(meth)acrylate” refers to methacrylate and/or acrylate.

The term “(meth)acrylamido” refers to a group of

in which R′ is hydrogen or C₁-C₄-alkyl and R″ is hydrogen or methyl.

The term “(meth)acryloxy” refers to a group of

in which R″ is hydrogen or methyl.

A “hydrophilic vinylic monomer”, as used herein, refers to a vinylicmonomer which as a homopolymer typically yields a polymer that iswater-soluble or can absorb at least 10 percent by weight water.

A “hydrophobic vinylic monomer”, as used herein, refers to a vinylicmonomer which as a homopolymer typically yields a polymer that isinsoluble in water and can absorb less than 10 percent by weight water.

A “blending vinylic monomer” refers to a vinylic monomer capable ofdissolving both hydrophilic and hydrophobic components of apolymerizable composition to form a solution.

A “macromer” or “prepolymer” refers to a compound or polymer thatcontains ethylenically unsaturated groups and has a number-averagemolecular weight (Mn) greater than 700 Daltons.

A “polymer” means a material formed by polymerizing/crosslinking one ormore vinylic monomers, macromers and/or prepolymers.

“Molecular weight” of a polymeric material (including monomeric ormacromeric materials), as used herein, refers to the number-averagemolecular weight unless otherwise specifically noted or unless testingconditions indicate otherwise.

The term “alkyl” refers to a monovalent radical obtained by removing ahydrogen atom from a linear or branched alkane compound. An alkyl group(radical) forms one bond with one other group in an organic compound.

The term “alkylene” refers to a divalent radical obtained by removingone hydrogen atom from an alkyl. An alkylene group (or radical) formstwo bonds with other groups in an organic compound.

In this application, the term “substituted” in reference to an alkylenedivalent radical or an alkyl radical means that the alkylene divalentradical or the alkyl radical comprises at least one substituent whichreplaces one hydrogen atom of the alkylene or alkyl radical and isselected from the group consisting of hydroxyl, carboxyl, —NH₂,sulfhydryl, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio (alkyl sulfide),C₁-C₄ acylamino, C₁-C₄ alkylamino, di-C₁-C₄ alkylamino, halogen atom (Bror Cl), and combinations thereof.

As used herein, the term “multiple” refers to three or more.

A “vinylic crosslinker” refers to a compound having at least twoethylenically-unsaturated groups. A “vinylic crosslinking agent” refersto a compound with two or more ethylenically unsaturated groups and withmolecular weight less than 700 Daltons.

A free radical initiator can be either a photoinitiator or a thermalinitiator. A “photoinitiator” refers to a chemical that initiates freeradical crosslinking/polymerizing reaction by the use of light. A“thermal initiator” refers to a chemical that initiates radicalcrosslinking/polymerizing reaction by the use of heat energy.

A “polymerizable UV-absorbing agent” or “UV-absorbing vinylic monomer”refers to a compound comprising an ethylenically-unsaturated group and aUV-absorbing moiety.

A “UV-absorbing moiety” refers to an organic functional group which canabsorb or screen out UV radiation in the range from 200 nm to 400 nm asunderstood by a person skilled in the art.

A “spatial limitation of actinic radiation” refers to an act or processin which energy radiation in the form of rays is directed by, forexample, a mask or screen or combinations thereof, to impinge, in aspatially restricted manner, onto an area having a well definedperipheral boundary. A spatial limitation of UV/visible radiation isobtained by using a mask or screen having a radiation (e.g., UV/visible)permeable region, a radiation (e.g., UV/visible) impermeable regionsurrounding the radiation-permeable region, and a projection contourwhich is the boundary between the radiation-impermeable andradiation-permeable regions, as schematically illustrated in thedrawings of U.S. Pat. No. 6,800,225 (FIGS. 1-11), and U.S. Pat. No.6,627,124 (FIGS. 1-9), U.S. Pat. No. 7,384,590 (FIGS. 1-6), and U.S.Pat. No. 7,387,759 (FIGS. 1-6), all of which are incorporated byreference in their entireties. The mask or screen allows to spatiallyprojects a beam of radiation (e.g., UV/visible radiation) having across-sectional profile defined by the projection contour of the mask orscreen. The projected beam of radiation (e.g., UV/visible radiation)limits radiation (e.g., UV/visible radiation) impinging on alens-forming material located in the path of the projected beam from thefirst molding surface to the second molding surface of a mold. Theresultant contact lens comprises an anterior surface defined by thefirst molding surface, an opposite posterior surface defined by thesecond molding surface, and a lens edge defined by the sectional profileof the projected UV/visible beam (i.e., a spatial limitation ofradiation). The radiation used for the crosslinking is a radiationenergy, especially UV/visible radiation, gamma radiation, electronradiation or thermal radiation, the radiation energy preferably being inthe form of a substantially parallel beam in order on the one hand toachieve good restriction and on the other hand efficient use of theenergy.

In the conventional cast-molding process, the first and second moldingsurfaces of a mold are pressed against each other to form acircumferential contact line which defines the edge of a result contactlens. Because the close contact of the molding surfaces can damage theoptical quality of the molding surfaces, the mold cannot be reused. Incontrast, in the Lightstream Technology™, the edge of a resultantcontact lens is not defined by the contact of the molding surfaces of amold, but instead by a spatial limitation of radiation. Without anycontact between the molding surfaces of a mold, the mold can be usedrepeatedly to produce high quality contact lenses with highreproducibility.

“Dye” means a substance that is soluble in a lens-forming fluid materialand that is used to impart color. Dyes are typically translucent andabsorb but do not scatter light.

A “pigment” means a powdered substance (particles) that is suspended ina lens-forming composition in which it is insoluble.

“Surface modification” or “surface treatment”, as used herein, meansthat an article has been treated in a surface treatment process (or asurface modification process) prior to or posterior to the formation ofthe article, in which (1) a coating is applied to the surface of thearticle, (2) chemical species are adsorbed onto the surface of thearticle, (3) the chemical nature (e.g., electrostatic charge) ofchemical groups on the surface of the article are altered, or (4) thesurface properties of the article are otherwise modified. Exemplarysurface treatment processes include, but are not limited to, a surfacetreatment by energy (e.g., a plasma, a static electrical charge,irradiation, or other energy source), chemical treatments, the graftingof hydrophilic vinylic monomers or macromers onto the surface of anarticle, mold-transfer coating process disclosed in U.S. Pat. No.6,719,929 (herein incorporated by reference in its entirety), theincorporation of wetting agents into a lens formulation for makingcontact lenses proposed in U.S. Pat. Nos. 6,367,929 and 6,822,016(herein incorporated by references in their entireties), reinforcedmold-transfer coating disclosed in U.S. Pat. No. 7,858,000 (hereinincorporated by reference in its entirety), and a hydrophilic coatingcomposed of covalent attachment or physical deposition of one or morelayers of one or more hydrophilic polymer onto the surface of a contactlens disclosed in U.S. Pat. Nos. 8,147,897 and 8,409,599 and US PatentApplication Publication Nos. 2011/0134387, 2012/0026457 and 2013/0118127(herein incorporated by references in their entireties).

“Post-curing surface treatment”, in reference to a silicone hydrogelmaterial or a soft contact lens, means a surface treatment process thatis performed after the formation (curing) of the hydrogel material orthe soft contact lens in a mold.

A “hydrophilic surface” in reference to a silicone hydrogel material ora contact lens means that the silicone hydrogel material or the contactlens has a surface hydrophilicity characterized by having an averagedwater contact angle of about 90 degrees or less, preferably about 80degrees or less, more preferably about 70 degrees or less, morepreferably about 60 degrees or less.

An “average contact angle” refers to a water contact angle (advancingangle measured by Sessile Drop), which is obtained by averagingmeasurements of at least 3 individual contact lenses.

The intrinsic “oxygen permeability”, Dk, of a material is the rate atwhich oxygen will pass through a material. As used in this application,the term “oxygen permeability (Dk)” in reference to a hydrogel (siliconeor non-silicone) or a contact lens means a measured oxygen permeability(Dk) which is corrected for the surface resistance to oxygen flux causedby the boundary layer effect according to the procedures shown inExamples hereinafter. Oxygen permeability is conventionally expressed inunits of barrers, where “barrer” is defined as [(cm³oxygen)(mm)/(cm²)(sec)(mm Hg)]×10⁻¹⁰.

The “oxygen transmissibility”, Dk/t, of a lens or material is the rateat which oxygen will pass through a specific lens or material with anaverage thickness of t [in units of mm] over the area being measured.Oxygen transmissibility is conventionally expressed in units ofbarrers/mm, where “barrers/mm” is defined as [(cm³ oxygen)/(cm²)(sec)(mmHg)]×10⁻⁹.

A “chain-extended polydiorganosiloxane vinylic crosslinker” refers to acompound which comprises at least two ethylenically unsaturated groupsand at least two polydiorganosiloxane segments separated by a linkage.

As used in this application, the term “clear” in reference to alens-forming composition means that the lens-forming composition is atransparent solution or liquid mixture (i.e., having a lighttransmissibility of 85% or greater, preferably 90% or greater in therange between 400 to 700 nm).

In general, the invention is directed to a class of polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymers which eachcomprise: (1) a linear polymer chain comprising at least twopolydimethylsiloxane segments, one hydrophilic polyoxyalkylene segmentbetween each pair of polydimethylsiloxane segments, and one amide-richlinker between each pair of one polydimethylsiloxane segment and onehydrophilic polyoxyalkylene segment; (2) two terminal (meth)acryloylgroups, wherein the polydimethylsiloxane-polyoxyalkylene block copolymerhas an average molecular weight of at least 3000 Daltons.

There are several potential unique features associated with use ofchain-extended polydiorganosiloxane vinylic crosslinkers of theinvention in making silicone hydrogel contact lens.

First, a polymerizable polydimethylsiloxane-polyoxyalkylene blockcopolymer of the invention is more compatible with other hydrophilicpolymerizable components (e.g., hydrophilic vinylic monomer, hydrophiliccrosslinking agent, and/or hydrophilic prepolymer), because of thepresence of at least one hydrophilic polymer segment. It is suitable forpreparing various solvent-containing or solventless lens formulationswhich can contain a large amount of hydrophilic polymerizable componentand are still clear at room temperature or even at a low storagetemperature of from about 0° C. to about 4° C. Such a lens formulationcan be advantageously prepared in advance in the production.

Second, because each polydimethylsiloxane segment has at least 5dimethylsiloxane units in a consecutive sequence, a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of the inventionmay be used to efficiently provide relatively-high oxygen permeabilityper siloxane unit without adversely affecting its compatibility withother hydrophilic polymerizable components.

Third, a polymerizable polydimethylsiloxane-polyoxyalkylene blockcopolymer of the invention is prepared according to two well-known clickreactions: thiol-lactone ring-opening reaction and thiol-MichaelAddition reaction.

Fourth, there is no need for the isolation and purification ofintermediate chemicals in the preparation of a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of the invention.

The present invention, in one aspect, provides a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of formula (I)

in which:

-   -   n1 is an integer of from 5 to 50;    -   t1 is an integer of from 1 to 15;    -   X₀ is O or NR′ in which R′ is hydrogen or C₁-C₄-alkyl;    -   R″ is hydrogen or methyl;    -   R₁ and R₂ independent of each other are a C₁-C₆ alkylene        divalent radical or a C₁-C₆ alkylene-oxy-C₁-C₆ alkylene divalent        radical;    -   pOAlk is a divalent radical of formula (II)

-   -   in which EO is an oxyethylene unit (—CH₂CH₂O—), PO is an        oxypropylene unit

-   -    and BO is an oxybutylene unit

-   -    e1 is an integer of 5 to 100, p1 and b1 independent of each        other are an integer of 0 to 50, provided that (e1+p1+b1)≥10,        and if (p1+b1)≥1, e1/(p1+b1)≥2 (preferably from about 2:1 to        about 10:1, more preferably from about 3:1 to about 6:1);    -   hpL is a divalent radical of formula (III) or (IV)

-   -   in which R₃ and R₄ independent of each other are a substituted        or unsubstituted C₁-C₁₂ alkylene divalent radical, R_(a) is        hydrogen or methyl (preferably hydrogen), and R_(b) is hydrogen,        C₁-C₃ alkyl, acetyl, or C₂-C₄ alkanoylamino (e.g., acetylamino,        propionylamino, butyrylamino) which optionally has a carboxyl        group (preferably acetylamino, propionylamino or butyrylamino,        more preferably acetylamino or propionylamino, even more        preferably acetylamino),        wherein the chain-extended polydiorganosiloxane vinylic        crosslinker has an average molecular weight of at least 3000        Daltons.

In accordance with a preferred embodiment, a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of formula (I) hasan average molecular weight of preferably from about 4000 Daltons toabout 100,000 Daltons, more preferably from about 5000 Daltons to about50,000 Dalton, even more preferably from about 7000 Daltons to about25,000 Daltons.

A polymerizable polydimethylsiloxane-polyoxyalkylene block copolymer offormula (I) can be prepared in a 2-step reaction scheme. In the firststep, a diamino-terminated polyoxyalkylene can be reacted withN-acetylhomocysteine thiolactone (or any thiolactone) to obtain adithiol-terminated polyoxyalkylene. In the second step, thedithiol-terminated polyoxyalkylene can be reacted with adi-(meth)acryloyl-terminated polydimethylsiloxane according to ThiolMichael Addition reaction, to obtain a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of formula (I). Itis understood that the molar equivalent ratio of dithiol-terminatedpolyoxyalkylene to di-(meth)acryloyl-terminated polydimethylsiloxaneshould be less than 1 in order to obtained di-(meth)acryloyl-terminatedpolydimethylsiloxane-polyoxyalkylene block copolymer. A person skilledin the art knows how to control the number of polydimethylsiloxanesegments in the resultant (meth)acryloyl-terminatedpolydimethylsiloxane-polyoxyalkylene block copolymer by varying themolar equivalent ratio of dithiol-terminated polyoxyalkylene todi-(meth)acryloyl-terminated polydimethylsiloxane.

As an illustrative example, Scheme 1 shows how to prepare apolymerizable polymerizable polydimethylsiloxane-polyoxyalkylene blockcopolymer of formula (I) from diaminoalkyl-terminated polyoxyethylene(H₂N—R₃-(EO)_(e1)—R₄—NH₂), N-acetylhomocysteine thiolactone, anddiacrylamido-terminated polydimethylsiloxane. It is understood that thediaminoalkyl-terminated polyoxyethylene can be replaced by adiaminoalkyl-terminated polyoxyethylene-polyoxypropylene di- ortri-block copolymer or a diaminoalkyl-terminatedpolyoxyethylene-polyoxybutylene di- or tri-block copolymer, and/or thatthe diacrylamido-terminated polydimethylsiloxane can be replaced by adimethacrylamido-terminated polydimethylsiloxane or adi-(meth)acryloyloxy-terminated polydimethylsiloxane, to obtain apolymerizable polydimethylsiloxane-polyoxyalkylene block copolymer offormula (I).

It is understood that, in the first step in Scheme 1, N-acetylhomocysteine thiolactone can be substituted with any thiolactone toobtain a hydrophilic copolymer of the invention. Examples of preferredcommercially-available thiolactone include without limitation4-butyrothiolactone (or dihydro-2(3H)-thiophenone),3-methyldihydro-2(3H)-thiophenone, 3-ethyldihydro-2(3H)-thiophenone,3-(1-methylethyl)dihydro-2(3H)-thiophenone,3,3-dimethyldihydro-2(3H)-thiophenone,3-ethyl-3-methyldihydro-2(3H)-thiophenone,3-acetyldihydro-2(3H)-thiophenone, N-acetyl homocysteine thiolactone,N-propionyl homocysteine thiolactone, N-butyryl homocysteinethiolactone, and N-carboxybutyryl homocysteine thilactone (or4-oxo-4-[(tetrahydro-2-oxo-3-thienyl)amino]-butanoic acid).

Any di-(meth)acryloyl-terminated polydimethylsiloxanes can be used inthe invention. Examples of preferred di-(meth)acryloyl-terminatedpolydimethylsiloxanes include without limitationα,ω-bis[3-(meth)acrylamidopropyl]-terminated polydimethylsiloxane,α,ω-bis[3-(meth)acryloxypropyl]-terminated polydimethylsiloxane,α,ω-bis[(meth)acryloxyethoxypropyl]-terminated polydimethylsiloxane,α,ω-bis[3-(meth)acryloxy-2-hydroxypropyloxypropyl]-terminatedpolydimethylsiloxane,α,ω-bis[3-(meth)acryloxyethoxy-2-hydroxypropyloxypropyl]-terminatedpolydimethylsiloxane,α,ω-bis[3-(meth)acryloxyethylamino-2-hydroxypropyloxy-propyl]-terminatedpolydimethylsiloxane,α,ω-bis[3-(meth)acrylamidoethoxy-2-hydroxypropyloxypropyl]-terminatedpolydimethylsiloxane,α,ω-bis[(meth)acrylamide-ethylamino-2-hydroxypropyloxypropyl]-terminatedpolydimethylsiloxane,α,ω-bis[3-(meth)acryloxypropoxy-2-hydroxypropyloxypropyl]-terminatedpolydimethylsiloxane,α,ω-bis[3-(meth)acryloxypropylamino-2-hydroxypropyloxypropyl]-terminatedpolydimethylsiloxane,α,ω-bis[3-(meth)acrylamidopropoxy-2-hydroxypropyloxypropyl]-terminatedpolydimethylsiloxane,α,ω-bis[3-(meth)acrylamidopropylamino-2-hydroxypropyloxypropyl]-terminatedpolydimethylsiloxane,α,ω-bis[3-(meth)acrylamidoisopropoxy-2-hydroxypropyloxypropyl]-terminatedpolydimethylsiloxane,α,ω-bis[(meth)acryloxy-2-hydroxypropyloxy-ethoxypropyl]-terminatedpolydimethylsiloxane,α,ω-bis[(meth)acryloxy-2-hydroxypropyl-N-ethylaminopropyl]-terminatedpolydimethylsiloxane,α,ω-bis[(meth)acryloxy-2-hydroxypropyl-aminopropyl]-polydimethylsiloxane,α,ω-bis-[(meth)acryloxy-2-hydroxypropyl-oxycabonylpropyl]-terminatedpolydimethylsiloxane,α,ω-bis[(meth)acryloxy-2-hydroxypropyl-oxy-pentylcabonyloxyalkyl]-terminatedpolydimethylsiloxane, andα,ω-bis-[(meth)acryloxy-2-hydroxypropyl-oxy(polyethylenoxy)propyl]-terminatedpolydimethylsiloxane.

Any diamino-terminated polyoxyethylenes, diamino-terminatedpolypolyoxyethylene-polyoxypropylene di-block copolymers,diamino-terminated polypolyoxyethylene-polyoxypropylene tri-blockcopolymers, diamino-terminated polypolyoxyethylene-polyoxybutylenedi-block copolymers, diamino-terminatedpolypolyoxyethylene-polyoxybutylene tri-block copolymers can be used inthe invention. They can be obtained from commercial sources.Alternatively, they can be prepared from dihydroxy-terminatedpolyoxyalkylene according to methods known to a person skilled in theart, e.g., those described in U.S. Pat. Nos. 4,179,337 and 5,206,344,U.S. Pat. Appl. Pub. No. 20030149307, and in the papers published by DeVos and Goethals (Makromol. Chem., Rapid Commun. 6, 53-56 (1985)) and byBuckmann et al. (Biotechnology and Applied Biochemistry 9, 258-268(1987)), herein incorporated by references in their entireties.

The dihydroxy-terminated polypolyoxyethylene-polyoxybutylene blockcopolymers may be synthesized according to procedures described in U.S.Pat. No. 8,318,144 (herein incorporated in reference in its entirety).

In accordance with the invention, diamino-terminated polyoxyakyleneutilized in the present invention have a molecular weight in the rangeof preferably from 250 to about 50,000 Daltons; and more preferably fromabout 500 to about 10,000 Daltons.

A polymerizable polymerizable polydimethylsiloxane-polyoxyalkylene blockcopolymer of the invention (formula (I) as defined above) can findparticular use in preparing a polymer, preferably a silicone hydrogelpolymeric material, which is another aspect of the invention. A personskilled in the art knows how to prepare a polymer or a silicone hydrogelpolymeric material from a polymerizable composition according to anyknown polymerization mechanism.

In another aspect, the invention provides a silicone hydrogel contactlens comprising a crosslinked polymeric material comprising: units of apolymerizable polydimethylsiloxane-polyoxyalkylene block copolymer offormula (I) (as defined above), units of a siloxane-containing vinylicmonomer, units of at least one hydrophilic vinylic monomer, wherein thesilicone hydrogel contact lens, when being fully hydrated, has an oxygenpermeability (Dk) of at least about 70 barrers (preferably at leastabout 80 barrers, more preferably at least about 90 barrers, even morepreferably at least about 100 barrers), a water content of from about25% to about 70% by weight (preferably from about 30% to about 65% byweight, more preferably from about 35% to about 60% by weight, even morepreferably from about 40% to about 55% by weight), an elastic modulus offrom about 0.20 MPa to about 1.2 MPa (preferably from about 0.25 MPa toabout 1.0 MPa, more preferably from about 0.3 MPa to about 0.9 MPa, evenmore preferably from about 0.4 MPa to about 0.8 MPa).

A person skilled in the art knows well how to measure the oxygenpermeability, oxygen transmissibility, water content, elastic modulus,and lens diameter of silicone hydrogel contact lenses. These lensproperties have been reported by all manufacturers for their siliconehydrogel contact lens products.

Various embodiments of a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of formula (I) (asdefined above) should be incorporated into this aspect of the invention.

Any suitable siloxane-containing vinylic monomers can be used in theinvention. A class of preferred siloxane-containing vinylic monomers isthose containing a tris(trialkylsiloxy)silyl group or abis(trialkylsilyloxy)alkylsilyl group. Examples of such preferredsilicone-containing vinylic monomers include without limitation3-acrylamidopropyl-bis(trimethylsiloxy)methylsilane, 3-N-methylacrylamidopropylbis(trimethylsiloxy)methylsilane,N-[tris(trimethylsiloxy)silylpropyl]-(meth)acrylamide,N-[tris(dimethylpropylsiloxy)-silylpropyl]-(meth)acrylamide,N-[tris(dimethylphenylsiloxy)silylpropyl] (meth)acrylamide,N-[tris(dimethylethylsiloxy)silylpropyl] (meth)acrylamide,N-(2-hydroxy-3-(3-(bis(trimethylsilyloxy)methylsilyl)propyloxy)propyl)-2-methylacrylamide;N-(2-hydroxy-3-(3-(bis(trimethylsilyloxy)methylsilyl)propyloxy)propyl)acrylamide;N,N-bis[2-hydroxy-3-(3-(bis(trimethylsilyloxy)methylsilyl)propyloxy)propyl]-2-methylacrylamide;N,N-bis[2-hydroxy-3-(3-(bis(trimethylsilyloxy)methylsilyl)propyloxy)propyl]acrylamide;N-(2-hydroxy-3-(3-(tris(trimethylsilyloxy)silyl)propyloxy)propyl)-2-methylacrylamide;N-(2-hydroxy-3-(3-(tris(trimethylsilyloxy)silyl)propyloxy)propyl)acrylamide;N,N-bis[2-hydroxy-3-(3-(tris(trimethylsilyloxy)silyl)propyloxy)propyl]-2-methylacrylamide;N,N-bis[2-hydroxy-3-(3-(tris(trimethylsilyloxy)silyl)propyloxy)propyl]acrylamide;N-[2-hydroxy-3-(3-(t-butyldimethylsilyl) propyloxy)propyl]-2-methylacrylamide;N-[2-hydroxy-3-(3-(t-butyldimethylsilyl)propyloxy)propyl]acrylamide;N,N-bis[2-hydroxy-3-(3-(t-butyldimethylsilyl)propyloxy)propyl]-2-methylacrylamide;N,N-bis[2-hydroxy-3-(3-(t-butyldimethylsilyl)propyloxy)propyl]acrylamide;3-methacryloxy propylpentamethyldisiloxane,tris(trimethylsilyloxy)silylpropyl methacrylate (TRIS),(3-methacryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane),(3-methacryloxy-2-hydroxypropyloxy)propyltris(trimethylsiloxy)silane,3-methacryloxyethoxypropyloxy-propyl-bis(trimethylsiloxy)methylsilane,N-2-methacryloxyethyl-O-(methyl-bis-trimethylsiloxy-3-propyl)silylcarbamate,3-(trimethylsilyl)propylvinyl carbonate,3-(vinyloxycarbonylthio)propyl-tris(trimethyl-siloxy)silane,3-[tris(trimethylsiloxy)silyl]propylvinyl carbamate,3-[tris(trimethylsiloxy)silyl] propyl allyl carbamate,3-[tris(trimethylsiloxy)silyl]propyl vinyl carbonate,t-butyldimethyl-siloxyethyl vinyl carbonate, trimethylsilylethyl vinylcarbonate, trimethylsilylmethyl vinyl carbonate, and hydrophlizedsiloxane-containing vinylic monomers disclosed in U.S. Pat. Nos.9,103,965, 9,475,827, and 9,097,840 (herein incorporated by referencesin their entireties) which comprise at least one hydrophilic linkageand/or at least one hydrophilic chain.

Another class of preferred siloxane-containing vinylic monomers ispolycarbosiloxane vinylic monomers (or carbosiloxane vinylic monomers).Examples of such polycarbosiloxane vinylic monomers or macromers arethose described in U.S. Pat. Nos. 7,915,323 and 8,420,711, in US PatentApplication Publication Nos. 2012/244088, 2012/245249, 2015/0309211, and2015/0309210 (herein incorporated by references in their entireties).

A further class of preferred siloxane-containing vinylic monomers ispolydimethylsiloxane-containing vinylic monomers. Examples of suchpolydimethylsiloxane-containing vinylic monomers aremono-(meth)acryloxy-terminated polydimethylsiloxanes of variousmolecular weight (e.g., mono-3-methacryloxypropyl terminated, mono-butylterminated polydimethylsiloxane ormono-(3-methacryloxy-2-hydroxypropyloxy) propyl terminated, mono-butylterminated polydimethylsiloxane), mono-(meth)acrylamido-terminatedpolydimethylsiloxanes of various molecular weight, or combinationsthereof.

In accordance with the invention, a siloxane-containing vinylic monomeris preferably3-(meth)acryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane,3-(meth)acryloxyethoxypropyloxypropylbis(trimethylsiloxy)methylsilane,3-(meth)acrylamidopropyl-bis(trimethylsiloxy)methylsilane, 3-N-methyl(meth)acrylamidopropylbis(trimethylsiloxy) methylsilane,mono-(meth)acryloxy-terminated polydimethylsiloxanes of variousmolecular weight, mono-(meth)acrylamido-terminated polydimethylsiloxanesof various molecular weight, or a combination thereof.

It is understood that the crosslinked polymeric material of a siliconehydrogel contact lens of the invention can optionally comprise apolydimethylsiloxane vinylic crosslinker so long it is compatible withthe hydrophilic polymerizable components in a lens-forming compositionfor making the silicone hydrogel contact lens.

Examples of preferred hydrophilic vinylic monomers include withoutlimitation N-vinylpyrrolidone, N,N-dimethyl (meth)acrylamide,(meth)acrylamide, hydroxylethyl (meth)acrylamide, hydroxyethyl(meth)acrylate, glycerol methacrylate (GMA), polyethylene glycol(meth)acrylate, polyethylene glycol C₁-C₄-alkyl ether (meth)acrylatehaving a weight average molecular weight of up to 1500, N-vinylformamide, N-vinyl acetamide, N-vinyl isopropylamide, N-vinyl-N-methylacetamide, N-methyl-3-methylene-2-pyrrolidone,1-ethyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone,1-ethyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone,5-ethyl-3-methylene-2-pyrrolidone, (meth)acrylic acid, ethylacrylicacid, and combinations thereof. Preferably, the hydrophilic vinylicmonomer is a hydrophilic N-vinyl monomer, such as, N-vinylpyrrolidone,N-vinyl-N-methyl acetamide, N-vinyl formamide, N-vinyl acetamide,N-vinyl isopropylamide, or combinations thereof. Even more preferably,the hydrophilic vinylic monomer is N-vinylpyrrolidone, N-vinyl-N-methylacetamide, or combinations thereof.

In accordance with the invention, the crosslinked polymeric material ofa silicone hydrogel contact lens of the invention can further compriseunits of a hydrophobic vinylic monomer free of silicone, units of anon-silicone vinylic crosslinker, units of a UV-absorbing vinylicmonomer, or a combination thereof.

Examples of preferred hydrophobic vinylic monomers includemethylacrylate, ethyl-acrylate, propylacrylate, isopropylacrylate,cyclohexylacrylate, 2-ethylhexylacrylate, methylmethacrylate, ethylmethacrylate, propylmethacrylate, vinyl acetate, vinyl propionate, vinylbutyrate, vinyl valerate, styrene, chloroprene, vinyl chloride,vinylidene chloride, acrylonitrile, 1-butene, butadiene,methacrylonitrile, vinyl toluene, vinyl ethyl ether,perfluorohexylethyl-thio-carbonyl-aminoethyl-methacrylate, isobornylmethacrylate, trifluoroethyl methacrylate, hexafluoro-isopropylmethacrylate, hexafluorobutyl methacrylate.

Examples of preferred non-silicone crosslinkers include withoutlimitation ethyleneglycol di-(meth)acrylate, diethyleneglycoldi-(meth)acrylate, triethyleneglycol di-(meth)acrylate,tetraethyleneglycol di-(meth)acrylate, glycerol di-(meth)acrylate,1,3-propanediol di-(meth)acrylate, 1,3-butanediol di-(meth)acrylate,1,4-butanediol di-(meth)acrylate, glycerol 1,3-diglycerolatedi-(meth)acrylate, ethylenebis[oxy(2-hydroxypropane-1,3-diyl)]di-(meth)acrylate, bis[2-(meth)acryloxyethyl] phosphate,trimethylolpropane di-(meth)acrylate, and3,4-bis[(meth)acryloyl]tetrahydrofuan, diacrylamide (i.e.,N-(1-oxo-2-propenyl)-2-propenamide), dimethacrylamide (i.e.,N-(1-oxo-2-methyl-2-propenyl)-2-methyl-2-propenamide),N,N-di(meth)acryloyl-N-methylamine, N,N-di(meth)acryloyl-N-ethylamine,N,N′-methylene bis(meth)acrylamide, N,N′-ethylene bis(meth)acrylamide,N,N′-dihydroxyethylene bis(meth)acrylamide, N,N′-propylenebis(meth)acrylamide, N,N′-2-hydroxypropylene bis(meth)acrylamide,N,N′-2,3-dihydroxybutylene bis(meth)acrylamide,1,3-bis(meth)acrylamidepropane-2-yl dihydrogen phosphate (i.e.,N,N′-2-phosphonyloxypropylene bis(meth)acrylamide), piperazinediacrylamide (or 1,4-bis(meth)acryloyl piperazine), vinyl methacrylate,allylmethacrylate, allylacrylate, N-allyl-methacrylamide,N-allyl-acrylamide, tetraethyleneglycol divinyl ether, triethyleneglycoldivinyl ether, diethyleneglycol divinyl ether, ethyleneglycol divinylether, triallyl isocyanurate, triallyl cyanurate, trimethylopropane trimethacrylate, pentaerythritol tetramethacrylate, bisphenol Adimethacrylate, a product of diamine (preferably selected from the groupconsisting of N,N′-bis(hydroxyethyl)ethylenediamine,N,N′-dimethylethylenediamine, ethylenediamine, N,N′-dimethyl-1,3-propanediamine, N, N′-diethyl-1,3-propanediamine,propane-1,3-diamine, butane-1,4-diamine, pentane-1,5-diamine,hexamethylenediamine, isophorone diamine, and combinations thereof) andepoxy-containing vinylic monomer (preferably selected from the groupconsisting of glycidyl (meth)acrylate, vinyl glycidyl ether, allylglycidyl ether, and combinations thereof), combinations thereof.

Examples of preferred UV-absorbing vinylic monomers include withoutlimitation: 2-(2-hydroxy-5-vinylphenyl)-2H-benzotriazole,2-(2-hydroxy-5-acrylyloxyphenyl)-2H-benzotriazole,2-(2-hydroxy-3-methacrylamido methyl-5-tert octylphenyl) benzotriazole,2-(2′-hydroxy-5′-methacrylamidophenyl)-5-chlorobenzotriazole,2-(2′-hydroxy-5′-methacrylamidophenyl)-5-methoxybenzotriazole,2-(2′-hydroxy-5′-methacryloxypropyl-3′-t-butyl-phenyl)-5-chlorobenzotriazole,2-(2′-hydroxy-5′-methacryloxypropylphenyl) benzotriazole,2-hydroxy-5-methoxy-3-(5-(trifluoromethyl)-2H-benzo[d][1,2,3]triazol-2-yl)benzylmethacrylate (WL-1),2-hydroxy-5-methoxy-3-(5-methoxy-2H-benzo[d][1,2,3]triazol-2-yl)benzylmethacrylate (WL-5),3-(5-fluoro-2H-benzo[d][1,2,3]triazol-2-yl)-2-hydroxy-5-methoxybenzylmethacrylate (WL-2),3-(2H-benzo[d][1,2,3]triazol-2-yl)-2-hydroxy-5-methoxybenzylmethacrylate (WL-3),3-(5-chloro-2H-benzo[d][1,2,3]triazol-2-yl)-2-hydroxy-5-methoxybenzylmethacrylate (WL-4),2-hydroxy-5-methoxy-3-(5-methyl-2H-benzo[d][1,2,3]triazol-2-yl)benzylmethacrylate (WL-6),2-hydroxy-5-methyl-3-(5-(trifluoromethyl)-2H-benzo[d][1,2,3]triazol-2-yl)benzylmethacrylate (WL-7),4-allyl-2-(5-chloro-2H-benzo[d][1,2,3]triazol-2-yl)-6-methoxyphenol(WL-8),2-{2′-Hydroxy-3′-tert-5[3″-(4″-vinylbenzyloxy)propoxy]phenyl}-5-methoxy-2H-benzotriazole,phenol,2-(5-chloro-2H-benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4-ethenyl-(UVAM),2-[2′-hydroxy-5′-(2-methacryloxyethyl)phenyl)]-2H-benzotriazole(2-Propenoic acid, 2-methyl-,2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl ester, Norbloc),2-{2′-Hydroxy-3′-tert-butyl-5′-[3′-methacryloyloxypropoxy]phenyl}-2H-benzotriazole,2-{2′-Hydroxy-3′-tert-butyl-5′-[3′-methacryloyloxypropoxy]phenyl}-5-methoxy-2H-benzotriazole(UV13),2-{2′-Hydroxy-3′-tert-butyl-5′-[3′-methacryloyloxypropoxy]phenyl}-5-chloro-2H-benzotriazole(UV28),2-[2′-Hydroxy-3′-tert-butyl-5′-(3′-acryloyloxypropoxy)phenyl]-5-trifluoromethyl-2H-benzotriazole(UV23), 2-(2′-hydroxy-5-methacrylamidophenyl)-5-methoxybenzotriazole(UV6), 2-(3-allyl-2-hydroxy-5-methylphenyl)-2H-benzotriazole (UV9),2-(2-Hydroxy-3-methallyl-5-methylphenyl)-2H-benzotriazole (UV12),2-3′-t-butyl-2′-hydroxy-5′-(3″-dimethylvinylsilylpropoxy)-2′-hydroxy-phenyl)-5-methoxybenzotriazole(UV15),2-(2′-hydroxy-5′-methacryloylpropyl-3′-tert-butyl-phenyl)-5-methoxy-2H-benzotriazole(UV16),2-(2′-hydroxy-5′-acryloylpropyl-3′-tert-butyl-phenyl)-5-methoxy-2H-benzotriazole(UV16A), 2-Methylacrylic acid3-[3-tert-butyl-5-(5-chlorobenzotriazol-2-yl)-4-hydroxyphenyl]-propylester (16-100, CAS#96478-15-8),2-(3-(tert-butyl)-4-hydroxy-5-(5-methoxy-2H-benzo[d][1,2,3]triazol-2-yl)phenoxy)ethylmethacrylate (16-102); Phenol,2-(5-chloro-2H-benzotriazol-2-yl)-6-methoxy-4-(2-propen-1-yl)(CAS#1260141-20-5);2-[2-Hydroxy-5-[3-(methacryloyloxy)propyl]-3-tert-butylphenyl]-5-chloro-2H-benzotriazole;Phenol, 2-(5-ethenyl-2H-benzotriazol-2-yl)-4-methyl-, homopolymer (901)(CAS#83063-87-0).

A silicone hydrogel contact lens can be prepared from a lens-formingcomposition according to a method of the invention which is anotheraspect of the invention.

In a further aspect, the present invention provides a method forproducing silicone hydrogel contact lenses. The method comprises thesteps of: preparing a lens-forming composition which is clear at roomtemperature and optionally but preferably at a temperature of from about0 to about 4° C., wherein the lens-forming composition comprises (a)from about 5% to about 35% by weight of a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of formula (I) (asdefined above), (b) a siloxane-containing vinylic monomer, (c) fromabout 30% to about 60% by weight of at least one hydrophilic vinylicmonomer, (d) at least one free-radical initiator, provided that theabove-listed polymerizable components and any additional polymerizablecomponents add up to 100% by weight; introducing the lens-formingcomposition into a mold, wherein the mold has a first mold half with afirst molding surface defining the anterior surface of a contact lensand a second mold half with a second molding surface defining theposterior surface of the contact lens, wherein said first and secondmold halves are configured to receive each other such that a cavity isformed between said first and second molding surfaces; curing thermallyor actinically the lens-forming composition in the lens mold to form asilicone hydrogel contact lens, wherein the silicone hydrogel contactlens has an oxygen permeability (Dk) of at least about 70 barrers, awater content of from about 25% to about 70% by weight, and an elasticmodulus of from about 0.2 MPa to about 1.2 MPa.

Various embodiments described above of a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of formula (I) (asdefined above) should be incorporated into this aspect of the invention.

Various embodiments described above of a siloxane-containing vinylicmonomer, a hydrophilic vinylic monomer should be incorporated in thisaspect of the invention.

In accordance with the invention, a free-radical initiator can be athermal initiator or photoinitiator.

Any thermal polymerization initiators can be used in the invention.Suitable thermal polymerization initiators are known to the skilledartisan and comprise, for example peroxides, hydroperoxides,azo-bis(alkyl- or cycloalkylnitriles), persulfates, percarbonates, ormixtures thereof. Examples of preferred thermal polymerizationinitiators include without limitation benzoyl peroxide, t-butylperoxide, t-amyl peroxybenzoate, 2,2-bis(tert-butylperoxy)butane,1,1-bis(tert-butylperoxy)cyclohexane,2,5-Bis(tert-butylperoxy)-2,5-dimethylhexane,2,5-bis(tert-butylperoxy)-2,5-dimethyl-3-hexyne,bis(1-(tert-butylperoxy)-1-methylethyl)benzene,1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane,di-t-butyl-diperoxyphthalate, t-butyl hydro-peroxide, t-butylperacetate, t-butyl peroxybenzoate, t-butylperoxy isopropyl carbonate,acetyl peroxide, lauroyl peroxide, decanoyl peroxide, dicetylperoxydicarbonate, di(4-t-butylcyclohexyl)peroxy dicarbonate (Perkadox16S), di(2-ethylhexyl)peroxy dicarbonate, t-butylperoxy pivalate(Lupersol 11); t-butylperoxy-2-ethylhexanoate (Trigonox 21-050),2,4-pentanedione peroxide, dicumyl peroxide, peracetic acid, potassiumpersulfate, sodium persulfate, ammonium persulfate,2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) (VAZO 33),2,2′-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride (VAZO 44),2,2′-azobis(2-amidinopropane) dihydrochloride (VAZO 50),2,2′-azobis(2,4-dimethylvaleronitrile) (VAZO 52),2,2′-azobis(isobutyronitrile) (VAZO 64 or AlBN),2,2′-azobis-2-methylbutyronitrile (VAZO 67),1,1-azobis(1-cyclohexanecarbonitrile) (VAZO 88);2,2′-azobis(2-cyclopropylpropionitrile), 2,2′-azobis(methylisobutyrate),4,4′-Azobis(4-cyanovaleric acid), and combinations thereof. Preferably,the thermal initiator is 2,2′-azobis(isobutyronitrile) (AlBN or VAZO64). The reaction time may vary within wide limits, but is conveniently,for example, from 1 to 24 hours or preferably from 2 to 12 hours. It isadvantageous to previously degas the components and solvents used in thepolymerization reaction and to carry out said copolymerization reactionunder an inert atmosphere, for example under a nitrogen or argonatmosphere.

Suitable photoinitiators are benzoin methyl ether, diethoxyacetophenone,a benzoylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone and Darocurand Irgacur types, preferably Darocur 1173® and Darocur 2959®,Germane-based Norrish Type I photoinitiators. Examples ofbenzoylphosphine initiators include2,4,6-trimethylbenzoyldiphenylophosphine oxide;bis-(2,6-dichlorobenzoyl)-4-N-propylphenylphosphine oxide; andbis-(2,6-dichlorobenzoyl)-4-N-butylphenylphosphine oxide. Reactivephotoinitiators which can be incorporated, for example, into a macromeror can be used as a special monomer are also suitable. Examples ofreactive photoinitiators are those disclosed in EP 632 329, hereinincorporated by reference in its entirety. The polymerization can thenbe triggered off by actinic radiation, for example light, in particularUV light of a suitable wavelength. The spectral requirements can becontrolled accordingly, if appropriate, by addition of suitablephotosensitizers.

Where a vinylic monomer capable of absorbing ultra-violet radiation andhigh energy violet light (HEVL) is used in the invention, aGermanium-based Norrish Type I photoinitiator and a light sourceincluding a light in the region of about 400 to about 550 nm arepreferably used to initiate a free-radical polymerization. AnyGermanium-based Norrish Type I photoinitiators can be used in thisinvention, so long as they are capable of initiating a free-radicalpolymerization under irradiation with a light in the region of about 400to about 550 nm. Examples of Germanium-based Norrish Type Iphotoinitiators are acylgermanium compounds described in U.S. Pat. No.7,605,190 (incorporated by reference in its entirety).

In a preferred embodiment, the lens-forming composition comprises anorganic solvent.

Example of suitable solvents includes without limitation,tetrahydrofuran, tripropylene glycol methyl ether, dipropylene glycolmethyl ether, ethylene glycol n-butyl ether, ketones (e.g., acetone,methyl ethyl ketone, etc.), diethylene glycol n-butyl ether, diethyleneglycol methyl ether, ethylene glycol phenyl ether, propylene glycolmethyl ether, propylene glycol methyl ether acetate, dipropylene glycolmethyl ether acetate, propylene glycol n-propyl ether, dipropyleneglycol n-propyl ether, tripropylene glycol n-butyl ether, propyleneglycol n-butyl ether, dipropylene glycol n-butyl ether, tripropyleneglycol n-butyl ether, propylene glycol phenyl ether dipropylene glycoldimetyl ether, polyethylene glycols, polypropylene glycols, ethylacetate, butyl acetate, amyl acetate, methyl lactate, ethyl lactate,i-propyl lactate, methylene chloride, 2-butanol, 1-propanol, 2-propanol,menthol, cyclohexanol, cyclopentanol and exonorborneol, 2-pentanol,3-pentanol, 2-hexanol, 3-hexanol, 3-methyl-2-butanol, 2-heptanol,2-octanol, 2-nonanol, 2-decanol, 3-octanol, norborneol, tert-butanol,tert-amyl, alcohol, 2-methyl-2-pentanol, 2,3-dimethyl-2-butanol,3-methyl-3-pentanol, 1-methylcyclohexanol, 2-methyl-2-hexanol,3,7-dimethyl-3-octanol, 1-chloro-2-methyl-2-propanol,2-methyl-2-heptanol, 2-methyl-2-octanol, 2-2-methyl-2-nonanol,2-methyl-2-decanol, 3-methyl-3-hexanol, 3-methyl-3-heptanol,4-methyl-4-heptanol, 3-methyl-3-octanol, 4-methyl-4-octanol,3-methyl-3-nonanol, 4-methyl-4-nonanol, 3-methyl-3-octanol,3-ethyl-3-hexanol, 3-methyl-3-heptanol, 4-ethyl-4-heptanol,4-propyl-4-heptanol, 4-isopropyl-4-heptanol, 2,4-dimethyl-2-pentanol,1-methylcyclopentanol, 1-ethylcyclopentanol, 1-ethylcyclopentanol,3-hydroxy-3-methyl-1-butene, 4-hydroxy-4-methyl-1-cyclopentanol,2-phenyl-2-propanol, 2-methoxy-2-methyl-2-propanol2,3,4-trimethyl-3-pentanol, 3,7-dimethyl-3-octanol, 2-phenyl-2-butanol,2-methyl-1-phenyl-2-propanol and 3-ethyl-3-pentanol,1-ethoxy-2-propanol, 1-methyl-2-propanol, t-amyl alcohol, isopropanol,1-methyl-2-pyrrolidone, N,N-dimethylpropionamide, dimethyl formamide,dimethyl acetamide, dimethyl propionamide, N-methyl pyrrolidinone, andmixtures thereof.

In another preferred embodiment, a lens-forming composition is asolution of all the desirable components dissolved in 1,2-propyleneglycol, a polyethyleneglycol having a molecular weight of about 400Daltons or less, or a mixture thereof.

In another preferred embodiment, the lens-forming composition is asolventless liquid mixture and comprises a blending vinylic monomerselected from the group consisting of a C₁-C₁₀ alkyl methacrylate,isobornylmethacrylate, isobornylacrylate, cyclopentylmethacrylate,cyclopentylacrylate, cyclohexylmethacrylate, cyclohexylacrylate,styrene, 2,4,6-trimethylstyrene (TMS), and t-butyl styrene (TBS), andcombinations thereof. Preferably, the blending vinylic monomer ismethylmethacrylate.

In another preferred embodiment, the total amount of allsilicone-containing polymerizable components present in the lens-formingcomposition is about 65% or less.

In another preferred embodiment, the hydrophilic vinylic monomer is ahydrophilic N-vinyl monomer, preferably is N-vinylpyrrolidone,N-vinyl-N-methyl acetamide, N-vinyl formamide, N-vinyl acetamide,N-vinyl isopropylamide, or combinations thereof, even more preferably isN-vinylpyrrolidone, N-vinyl-N-methyl acetamide, or combinations thereof.

In another preferred embodiment, the lens-forming composition furthercomprises a non-silicone vinylic crosslinker. Various embodimentsdescribed above of a siloxane-containing vinylic monomer, a hydrophilicvinylic monomer should be incorporated in this aspect of the invention.The amount of a non-silicone vinylic crosslinker used is expressed inthe weight content with respect to the total polymerizable componentsand is preferably in the range from about 0.05% to about 2%, and morepreferably in the range from about 0.1% to about 1.5%, even morepreferably in the range from about 0.15% to about 1.0%.

In accordance with the invention, the lens-forming composition canfurther comprise other components, such as, a visibility tinting agent(e.g., dyes, pigments, or mixtures thereof), antimicrobial agents (e.g.,preferably silver nanoparticles), a bioactive agent, leachablelubricants, leachable tear-stabilizing agents, and mixtures thereof, asknown to a person skilled in the art.

Lens molds for making contact lenses are well known to a person skilledin the art and, for example, are employed in cast molding or spincasting. For example, a mold (for cast molding) generally comprises atleast two mold sections (or portions) or mold halves, i.e. first andsecond mold halves. The first mold half defines a first molding (oroptical) surface and the second mold half defines a second molding (oroptical) surface. The first and second mold halves are configured toreceive each other such that a lens forming cavity is formed between thefirst molding surface and the second molding surface. The moldingsurface of a mold half is the cavity-forming surface of the mold and indirect contact with lens-forming material.

Methods of manufacturing mold sections for cast-molding a contact lensare generally well known to those of ordinary skill in the art. Theprocess of the present invention is not limited to any particular methodof forming a mold. In fact, any method of forming a mold can be used inthe present invention. The first and second mold halves can be formedthrough various techniques, such as injection molding or lathing.Examples of suitable processes for forming the mold halves are disclosedin U.S. Pat. No. 4,444,711 to Schad; U.S. Pat. No. 4,460,534 to Boehm etal.; U.S. Pat. No. 5,843,346 to Morrill; and U.S. Pat. No. 5,894,002 toBoneberger et al., which are also incorporated herein by reference.

Virtually all materials known in the art for making molds can be used tomake molds for making contact lenses. For example, polymeric materials,such as polyethylene, polypropylene, polystyrene, PMMA, Topas® COC grade8007-S10 (clear amorphous copolymer of ethylene and norbornene, fromTicona GmbH of Frankfurt, Germany and Summit, N.J.), or the like can beused. Other materials that allow UV light transmission could be used,such as quartz glass and sapphire.

In accordance with the invention, the lens-forming formulation (orcomposition) can be introduced (dispensed) into a cavity formed by amold according to any known methods.

After the lens-forming composition is dispensed into the mold, it ispolymerized to produce a contact lens. Crosslinking may be initiatedthermally or actinically.

Opening of the mold so that the molded article can be removed from themold may take place in a manner known per se.

The molded contact lens can be subject to lens extraction to removeunpolymerized polymerizable components. The extraction solvent can beany solvent known to a person skilled in the art. Examples of suitableextraction solvent are those described above. Preferably, water or anaqueous solution is used as extraction solvent. After extraction, lensescan be hydrated in water or an aqueous solution of a wetting agent(e.g., a hydrophilic polymer).

The molded contact lenses can further subject to further processes, suchas, for example, surface treatment, packaging in lens packages with apackaging solution which can contain about 0.005% to about 5% by weightof a wetting agent (e.g., a hydrophilic polymer described above or thelike known to a person skilled in the art) and/or a viscosity-enhancingagent (e.g., methyl cellulose (MC), ethyl cellulose,hydroxymethylcellulose, hydroxyethyl cellulose (HEC),hydroxypropylcellulose (HPC), hydroxypropylmethyl cellulose (HPMC), or amixture thereof); sterilization such as autoclave at from 118 to 124° C.for at least about 30 minutes; and the like.

In a preferred embodiment, the resultant silicone hydrogel contact lensis extracted with water or an aqueous solution.

In another preferred embodiment, the mold is a reusable mold and thelens-forming composition is cured (i.e., polymerized) actinically undera spatial limitation of actinic radiation to form a silicone hydrogelcontact lens. Examples of preferred reusable molds are those disclosedin U.S. Pat. Nos. 6,627,124, 6,800,225, 7,384,590, and 7,387,759, whichare incorporated by reference in their entireties. Reusable molds can bemade of quartz, glass, sapphire, CaF₂, a cyclic olefin copolymer (suchas for example, Topas® COC grade 8007-S10 (clear amorphous copolymer ofethylene and norbornene) from Ticona GmbH of Frankfurt, Germany andSummit, N.J., Zeonex® and Zeonor® from Zeon Chemicals LP, Louisville,Ky.), polymethylmethacrylate (PMMA), polyoxymethylene from DuPont(Delrin), Ultem® (polyetherimide) from G.E. Plastics, PrimoSpire®, andcombinations thereof.

Although various embodiments of the invention have been described usingspecific terms, devices, and methods, such description is forillustrative purposes only. The words used are words of descriptionrather than of limitation. It is to be understood that changes andvariations may be made by those skilled in the art without departingfrom the spirit or scope of the present invention, which is set forth inthe following claims. In addition, it should be understood that aspectsof the various embodiments may be interchanged either in whole or inpart or can be combined in any manner and/or used together, asillustrated below:

1. A polymerizable polydimethylsiloxane-polyoxyalkylene block copolymerof formula (I)

in which:

-   -   n1 is an integer of from 5 to 50;    -   t1 is an integer of from 1 to 15;    -   X₀ is O or NR′ in which R′ is hydrogen or C₁-C₄-alkyl;    -   R″ is hydrogen or methyl;    -   R₁ and R₂ independent of each other are a C₁-C₆ alkylene        divalent radical or a C₁-C₆ alkylene-oxy-C₁-C₆ alkylene divalent        radical;    -   pOAlk is a divalent radical of formula (II)

-   -   in which EO is an oxyethylene unit (—CH₂CH₂O—), PO is an        oxypropylene unit of

-   -    and BO is an oxybutylene unit of

-   -    e1 is an integer of 5 to 100, p1 and b1 independent of each        other are an integer of 0 to 50, provided that, (e1+p1+b1)≥10,        and if (p1+b1)≥1, e1/(p1+b1)≥2;    -   hpL is a divalent radical of formula (III) or (IV)

-   -   in which R₃ and R₄ independent of each other are a substituted        or unsubstituted C₁-C₁₂ alkylene divalent radical, R_(a) is        hydrogen or methyl, and R_(b) is hydrogen, C₁-C₃ alkyl, acetyl,        or C₂-C₄ alkanoylamino which optionally has a carboxyl group,        wherein the chain-extended polydiorganosiloxane vinylic        crosslinker has a number-average molecular weight of at least        3000 Daltons.        2. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to invention 1, wherein in formula (III)        and (IV) R_(a) is hydrogen.        3. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to invention 2, wherein in formula (III)        and (IV) R_(b) is hydrogen, acetylamino, propionylamino or        butyrylamino.        4. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to invention 2, wherein in formula (III)        and (IV) R_(b) is acetylamino, propionylamino or butyrylamino.        5. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to invention 2, wherein in formula (III)        and (IV) R_(b) is acetylamino or propionylamino.        6. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to invention 2, wherein in formula (III)        and (IV) R_(b) is acetylamino.        7. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to any one of inventions 1 to 6, wherein in        formula (II) (p1+b1)≥1 and e1/(p1+b1)≥2.        8. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to invention 7, wherein e1/(p1+b1) is from        about 2:1 to about 10:1.        9. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to invention 7, wherein e1/(p1+b1) is from        about 3:1 to about 6:1.        10. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to invention 7 or 8 or 9, wherein p1 is        zero.        11. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to invention 7 or 8 or 9, wherein b1 is        zero.        12. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to any one of inventions 1 to 6, wherein p1        and b1 both are zero and e1 is an integer of from 10 to 100.        13. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to any one of inventions 1 to 12, wherein        the polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer of formula (I) has a number-average molecular weight        of from about 4000 Daltons to about 100,000 Daltons.        14. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to any one of inventions 1 to 12, wherein        the polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer of formula (I) has a number-average molecular weight        of from about 5000 Daltons to about 50,000 Dalton.        15. The polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer according to any one of inventions 1 to 12, wherein        the polymerizable polydimethylsiloxane-polyoxyalkylene block        copolymer of formula (I) has a number-average molecular weight        of from about 7000 Daltons to about 25,000 Daltons).        16. A silicone hydrogel contact lens comprising a crosslinked        polymeric material which comprises:

units of a polymerizable polydimethylsiloxane-polyoxyalkylene blockcopolymer according to any one of inventions 1 to 15;

units of a siloxane-containing vinylic monomer;

units of at least one hydrophilic vinylic monomer,

wherein the silicone hydrogel contact lens, when being fully hydrated,has an oxygen permeability (Dk) of at least 70 barrers, a water contentof from about 25% to about 70% by weight, an elastic modulus of fromabout 0.2 MPa to about 1.2 MPa.

17. The silicone hydrogel contact lens according to invention 16,wherein the hydrophilic vinylic monomer is N-vinylpyrrolidone,N,N-dimethyl (meth)acrylamide, (meth)acrylamide, hydroxylethyl(meth)acrylamide, hydroxyethyl (meth)acrylate, glycerol methacrylate(GMA), polyethylene glycol (meth)acrylate, polyethylene glycolC₁-C₄-alkyl ether (meth)acrylate having a number-average molecularweight of up to 1500, N-vinyl formamide, N-vinyl acetamide, N-vinylisopropylamide, N-vinyl-N-methyl acetamide,N-methyl-3-methylene-2-pyrrolidone, 1-ethyl-3-methylene-2-pyrrolidone,1-methyl-5-methylene-2-pyrrolidone, 1-ethyl-5-methylene-2-pyrrolidone,5-methyl-3-methylene-2-pyrrolidone, 5-ethyl-3-methylene-2-pyrrolidone,(meth)acrylic acid, ethylacrylic acid, or combinations thereof.18. The silicone hydrogel contact lens according to invention 16,wherein the hydrophilic vinylic monomer is N-vinylpyrrolidone,N-vinyl-N-methyl acetamide, or combinations thereof.19. The silicone hydrogel contact lens according to any one ofinventions 16 to 18, wherein the crosslinked polymeric material furthercomprises units of a hydrophobic vinylic monomer free of silicone, unitsof a non-silicone vinylic crosslinker, units of a UV-absorbing vinylicmonomer, or a combination thereof.20. A method for producing silicone hydrogel contact lenses, comprisingthe steps of:

preparing a lens-forming composition which is clear at room temperatureand/or at a temperature of from about 0 to about 4° C., wherein thelens-forming composition comprises (a) from about 5% to about 35% byweight of a polymerizable polydimethylsiloxane-polyoxyalkylene blockcopolymer of any one of inventions 1 to 15, (b) a siloxane-containingvinylic monomer, (c) from about 30% to about 60% by weight of at leastone hydrophilic vinylic monomer, (d) at least one free-radicalinitiator, provided that the above-listed polymerizable components andany additional polymerizable components add up to 100% by weight;

introducing the lens-forming composition into a mold, wherein the moldhas a first mold half with a first molding surface defining the anteriorsurface of a contact lens and a second mold half with a second moldingsurface defining the posterior surface of the contact lens, wherein saidfirst and second mold halves are configured to receive each other suchthat a cavity is formed between said first and second molding surfaces;and

curing thermally or actinically the lens-forming composition in the lensmold to form a silicone hydrogel contact lens, wherein the siliconehydrogel contact lens has an oxygen permeability (Dk) of at least about70 barrers, a water content of from about 25% to about 70% by weight, anelastic modulus of from about 0.2 MPa to about 1.2 MPa.

21. The method according to invention 20, wherein the lens-formingcomposition is a solventless liquid mixture and comprises a blendingvinylic monomer selected from the group consisting of a C₁-C₁₀ alkylmethacrylate, isobornylmethacrylate, isobornylacrylate,cyclopentylmethacrylate, cyclopentylacrylate, cyclohexylmethacrylate,cyclohexylacrylate, styrene, 2,4,6-trimethylstyrene (TMS), and t-butylstyrene (TBS), and combinations thereof.22. The method according to invention 20 or 21, wherein the blendingvinylic monomer is methylmethacrylate.23. The method according to invention 20, wherein the lens-formingcomposition comprises an organic solvent.24. The method according to invention 23, wherein the organic solvent is1,2-propylene glycol, a polyethyleneglycol having a number-averagemolecular weight of about 400 Daltons or less, or a mixture thereof.25. The method according to any one of inventions 20 to 24, wherein thetotal amount of all silicone-containing polymerizable components presentin the lens-forming composition is about 65% or less.26. The method according to any one of inventions 20 to 25, wherein thehydrophilic vinylic monomer is a hydrophilic N-vinyl monomer.27. The method according to any one of inventions 20 to 26, wherein thehydrophilic vinylic monomer is a hydrophilic N-vinyl monomer which isN-vinylpyrrolidone, N-vinyl-N-methyl acetamide, N-vinyl formamide,N-vinyl acetamide, N-vinyl isopropylamide, or combinations thereof.28. The method according to any one of inventions 20 to 26, wherein thehydrophilic vinylic monomer is a hydrophilic N-vinyl monomer which isN-vinylpyrrolidone, N-vinyl-N-methyl acetamide, or combinations thereof.29. The method according to any one of inventions 20 to 28, wherein thehydrophilic vinylic monomer is N-vinylpyrrolidone, N-vinyl-N-methylacetamide, or combinations thereof.30. The method according to any one of inventions 20 to 29, wherein thelens-forming composition further comprises a non-silicone vinyliccrosslinker.31. The method according to invention 30, wherein the non-siliconevinylic crosslinker is selected from the group consisting ofethyleneglycol di-(meth)acrylate, diethyleneglycol di-(meth)acrylate,triethyleneglycol di-(meth)acrylate, tetraethyleneglycoldi-(meth)acrylate, glycerol di-(meth)acrylate, 1,3-propanedioldi-(meth)acrylate, 1,3-butanediol di-(meth)acrylate, 1,4-butanedioldi-(meth)acrylate, glycerol 1,3-diglycerolate di-(meth)acrylate,ethylenebis[oxy(2-hydroxypropane-1,3-diyl)] di-(meth)acrylate,bis[2-(meth)acryloxyethyl] phosphate, trimethylolpropanedi-(meth)acrylate, and 3,4-bis[(meth)acryloyl]tetrahydrofuan,diacrylamide (i.e., N-(1-oxo-2-propenyl)-2-propenamide),dimethacrylamide (i.e.,N-(1-oxo-2-methyl-2-propenyl)-2-methyl-2-propenamide),N,N-di(meth)acryloyl-N-methylamine, N,N-di(meth)acryloyl-N-ethylamine,N,N′-methylene bis(meth)acrylamide, N,N′-ethylene bis(meth)acrylamide,N,N′-dihydroxyethylene bis(meth)acrylamide, N,N′-propylenebis(meth)acrylamide, N,N′-2-hydroxypropylene bis(meth)acrylamide,N,N′-2,3-dihydroxybutylene bis(meth)acrylamide,1,3-bis(meth)acrylamidepropane-2-yl dihydrogen phosphate (i.e.,N,N′-2-phosphonyloxypropylene bis(meth)acrylamide), piperazinediacrylamide (or 1,4-bis(meth)acryloyl piperazine), vinyl methacrylate,allylmethacrylate, allylacrylate, N-allyl-methacrylamide,N-allyl-acrylamide, tetraethyleneglycol divinyl ether, triethyleneglycoldivinyl ether, diethyleneglycol divinyl ether, ethyleneglycol divinylether, triallyl isocyanurate, triallyl cyanurate, trimethylopropane trimethacrylate, pentaerythritol tetramethacrylate, bisphenol Adimethacrylate, combinations thereof.32. The method according to invention 30, wherein the non-siliconevinylic crosslinker is selected from the group consisting oftetra(ethyleneglycol) di-(meth)acrylate, tri(ethyleneglycol)di-(meth)acrylate, ethyleneglycol di-(meth)acrylate, di(ethyleneglycol)di-(meth)acrylate, glycerol dimethacrylate, allyl (meth)acrylate,N,N′-methylene bis(meth)acrylamide, N,N′-ethylene bis(meth)acrylamide,N,N′-dihydroxyethylene bis(meth)acrylamide, N,N′-2-hydroxypropylenebis(meth)acrylamide, N,N′-2,3-dihydroxybutylene bis(meth)acrylamide,1,3-bis(meth)acrylamidepropane-2-yl dihydrogen phosphate (i.e.,N,N′-2-phosphonyloxypropylene bis(meth)acrylamide), piperazinediacrylamide (or 1,4-bis(meth)acryloyl piperazine), triallylisocyanurate, tetraethyleneglycol divinyl ether, triethyleneglycoldivinyl ether, diethyleneglycol divinyl ether, ethyleneglycol divinylether, and combinations thereof.33. The method according to any one of inventions 20 to 32, wherein thesiloxane-containing vinylic monomer is3-(meth)acryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane,3-(meth)acryloxyethoxypropyloxypropylbis(trimethylsiloxy)methylsilane,3-(meth)acrylamidopropyl-bis(trimethylsiloxy)methylsilane, 3-N-methyl(meth)acrylamidopropyl-bis(trimethylsiloxy) methylsilane,mono-(meth)acryloxy-terminated polydimethylsiloxanes of variousnumber-average molecular weight, mono-(meth)acrylamido-terminatedpolydimethylsiloxanes of various molecular weight, or a combinationthereof.34. The method according to any one of inventions 20 to 33, wherein thestep of curing is carried out thermally.35. The method according to any one of inventions 20 to 34, wherein thelens-forming composition is clear at room temperature.

The previous disclosure will enable one having ordinary skill in the artto practice the invention. Various modifications, variations, andcombinations can be made to the various embodiment described herein. Inorder to better enable the reader to understand specific embodiments andthe advantages thereof, reference to the following examples issuggested. It is intended that the specification and examples beconsidered as exemplary.

Example 1

A polydimethylsiloxane-polyoxyalkylene block copolymer of the inventionis prepared according to the procedures shown in Scheme 1.

To a 500 mL jacketed reactor is added Jeffamine ED-900 (Aldrich14527-500 mL-F, lot#BCBG7025V, MW-900, 3.00 g, 1 molar eq.),DL-N-actylhomocysteine thiolactone (made by Jintan ShuibeiPharmaceutical Factory, lot#151112, 1.07 g, 2.02 molar eq.) andisopropanol (16.29 g). The reactor is maintained at 25° C. using acirculator, and protected under nitrogen. The reaction is run overnight.To the reaction mixture is added PDMS dimethacrylate (Shin-EtsuX-22-164B, lot#009051, MW˜5000, 16.00 g, 1.5 molar eq.),dimethylphenylphosphine (Aldrich 266020-5G, lot#MKBZ0750V, 47.4 μL, 0.1molar eq.) and isopropanol (32.00 g). The reaction is run for 24 hours.The reaction mixture is transferred out, and 40 g of the solution ispurified by repeated dialysis in isopropanol using Spectra/Por® membranewith a molecular weight cutoff of 1 k. After dialysis, the solution isconcentrated by rotovap to give a viscous opaque white liquid (15.65 g).

Example 2

A chain-extended polydimethylsiloxane vinylic crosslinker (CE-PDMS, M.W.˜9000 g/mol), which has three polydimethylsiloxane (PDMS) segmentslinked via diurethane linkages between two PDMS segments, is preparedaccording to the procedures similar to what described in Example 2 ofU.S. Pat. No. 8,529,057 (herein incorporated by reference in itsentirety).

Example 3

A low molecular weight chain-extended polydimethylsiloxane vinyliccrosslinker (LM CE-PDMS, M.W. ˜6000 g/mol), which has threepolydimethylsiloxane (PDMS) segments linked via diurethane linkagesbetween two PDMS segments, is prepared according to the proceduressimilar to what described in Example 2 of U.S. Pat. No. 8,529,057(herein incorporated by reference in its entirety).

Example 4 Synthesis of the Precursor

275.9 g of octamethylcyclotetrasiloxane (M.W. 296.62), 12.0 g of1,3,5,7-tetramethylcyclotetrasiloxane (M.W. 240.51), 9.7 g of1,3-bis(3-methacryloxypropyl) tetramethyldisiloxane (M.W. 386.63), and0.9 g of trifluoromethanesulfonic acid (M.W. 150.08) are weighed into a500 mL round bottom flask. After the reaction is run at 35° C. for 24 h,170 mL of 0.5% sodium hydrogen carbonate is added. The collected organicportion is further extracted five times with de-ionized water (170 mLper cycle). Anhydrous MgSO₄ is added to the collected organic solution,followed by ˜350 mL of additional CHCl₃, and the solution is thenstirred overnight. After filtration, the solvent is removed via Rotovap,followed by high vacuum. 102 g of final product (the precursor) isobtained.

Hydrosilylation Reaction with 3-Allyloxy-1,2-Propanediol to Form PDMSCrosslinker

A small reactor is connected to a heater and air condenser with dryingtube. 21 g of toluene, 15 g of above precursor, and 5.03 g of3-allyloxy-1,2-propanediol are added to the reactor. After the solutiontemperature is stabilized at 30° C., 152 μL of Karstedt's catalyst (2 Pt% in xylene) is added. After 2 h, the conversion of Si—H of 100% basedon IR is achieved. The solution is then transferred to a flask,concentrated using Rotovop, followed by precipitation inactenotrile/water mixture (75/25) three times. After removal of solventvia Rotovop, followed by high vacuum, 12 g of polydiorganosiloxanevinylic crosslinker with glycerol ether substituents (hazy liquid) isobtained.

Example 5 Synthesis of Glycerol Ether Containing PDMS Macromer (MacromerB)

Macromer B is prepared according to the procedures similar to whatdescribed in Example 2, except that the amounts of reactants in thefirst step for preparing precursor is changed. The obtainedpolydiorganosiloxane vinylic crosslinker with glycerol ethersubstituents has a structure formula

Example 6

Compatibility with Hydrophilic Vinylic Monomers

A polydimethylsiloxane-polyoxyalkylene block copolymer, prepared inExample 1, is studied for its compatibility with N-vinylpyrrolidone(NVP) at a weight ratio of 1:1 at room temperature. For comparison,vinylic crosslinkers prepared in Examples 2 to 5 are also included inthe study. Table 1 shows the results. It shows that a chain-extendedpolydimethylsiloxane vinylic crosslinker of the invention is mostcompatible with NVP.

TABLE 1 NVP/Crosslinker (wt. Crosslinker. ratio) Compatibility Example 11:1 Compatible - homogeneous Example 2 1:1 Not compatible - phaseseparation Example 3 1:1 Partially compatible - homogenous, but quitehazy Example 4 1:1 Not compatible - phase separation Example 5 1:1Compatible - homogenousIt is found that, like a polydiorganosiloxane vinylic crosslinker withhigher content of hydrophilic substituents (glycerol ether pendantchains), a polydimethylsiloxane-polyoxyalkylene block copolymer withhydrophilized linkages between polydimethylsiloxane segments is highlycompatible with hydrophilic vinylic monomer, NVP, as shown by itscapability to forming a homogeneous mixture at room temperature. Theseresults indicate that the presence of hydrophilized linkages in apolydimethylsiloxane-polyoxyalkylene block copolymer of the inventioncan improve the capability of the crosslinker with hydrophilic vinylicmonomers.

What is claimed is:
 1. A polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of formula (I)

in which: n1 is an integer of from 5 to 50; t1 is an integer of from 1to 15; X₀ is O or NR′ in which R′ is hydrogen or C₁-C₄-alkyl; R″ ishydrogen or methyl; R₁ and R₂ independent of each other are a C₁-C₆alkylene divalent radical or a C₁-C₆ alkylene-oxy-C₁-C₆ alkylenedivalent radical; pOAlk is a divalent radical of formula (II)

in which EO is an oxyethylene unit (—CH₂CH₂O—), PO is an oxypropyleneunit of

 and BO is an oxybutylene unit of

 e1 is an integer of 5 to 100, p1 and b1 independent of each other arean integer of 0 to 50, provided that (e1+p1+b1)≥10 and is (p1+b1)≥1,e1/(p1+b1)≥2; hpL is a divalent radical of formula (III) or (IV)

in which R₃ and R₄ independent of each other are a substituted orunsubstituted C₁-C₁₂ alkylene divalent radical, R_(a) is hydrogen ormethyl, and R_(b) is hydrogen, C₁-C₃ alkyl, acetyl, or C₂-C₄alkanoylamino which optionally has a carboxyl group, wherein thechain-extended polydiorganosiloxane vinylic crosslinker has anumber-average molecular weight of at least 3000 Daltons.
 2. Thepolymerizable polydimethylsiloxane-polyoxyalkylene block copolymeraccording to claim 1, wherein p1 is zero.
 3. The polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer according to claim1, wherein b1 is zero.
 4. The polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer according to claim1, wherein p1 and b1 both are zero and e1 is an integer of from 10 to100.
 5. A silicone hydrogel contact lens comprising a crosslinkedpolymeric material which comprises: units of a polymerizablepolydimethylsiloxane-polyoxyalkylene block copolymer of claim 1; unitsof a siloxane-containing vinylic monomer; units of at least onehydrophilic vinylic monomer, wherein the silicone hydrogel contact lens,when being fully hydrated, has an oxygen permeability (Dk) of at leastabout 70 barrers, a water content of from about 25% to about 70% byweight, an elastic modulus of from about 0.2 MPa to about 1.2 MPa. 6.The silicone hydrogel contact lens according to claim 5, wherein thehydrophilic vinylic monomer is N-vinylpyrrolidone, N,N-dimethyl(meth)acrylamide, (meth)acrylamide, hydroxylethyl (meth)acrylamide,hydroxyethyl (meth)acrylate, glycerol methacrylate (GMA), polyethyleneglycol (meth)acrylate, polyethylene glycol C₁-C₄-alkyl ether(meth)acrylate having a weight average molecular weight of up to 1500,N-vinyl formamide, N-vinyl acetamide, N-vinyl isopropylamide,N-vinyl-N-methyl acetamide, N-methyl-3-methylene-2-pyrrolidone,1-ethyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone,1-ethyl-5-methylene-2-pyrrolidone, 5-methyl-3-methylene-2-pyrrolidone,5-ethyl-3-methylene-2-pyrrolidone, (meth)acrylic acid, ethylacrylicacid, or combinations thereof.
 7. The silicone hydrogel contact lensaccording to claim 6, wherein the crosslinked polymeric material furthercomprises units of a hydrophobic vinylic monomer free of silicone, unitsof a non-silicone vinylic crosslinker, units of a UV-absorbing vinylicmonomer, or a combination thereof.
 8. A method for producing siliconehydrogel contact lenses, comprising the steps of: preparing alens-forming composition which is clear at room temperature and/or at atemperature of from about 0 to about 4° C., wherein the lens-formingcomposition comprises (a) from about 5% to about 35% by weight of apolymerizable polydimethylsiloxane-polyoxyalkylene block copolymer ofclaim 1, (b) a siloxane-containing vinylic monomer, (c) from about 30%to about 60% by weight of at least one hydrophilic vinylic monomer, (d)at least one free-radical initiator, provided that the above-listedpolymerizable components and any additional polymerizable components addup to 100% by weight; introducing the lens-forming composition into amold, wherein the mold has a first mold half with a first moldingsurface defining the anterior surface of a contact lens and a secondmold half with a second molding surface defining the posterior surfaceof the contact lens, wherein said first and second mold halves areconfigured to receive each other such that a cavity is formed betweensaid first and second molding surfaces; and curing thermally oractinically the lens-forming composition in the lens mold to form asilicone hydrogel contact lens, wherein the silicone hydrogel contactlens has an oxygen permeability (Dk) of at least about 70 barrers, awater content of from about 25% to about 70% by weight, and an elasticmodulus of from about 0.2 MPa to about 1.2 MPa.
 9. The method accordingto claim 8, wherein the lens-forming composition is a solventless liquidmixture and comprises a blending vinylic monomer selected from the groupconsisting of a C₁-C₁₀ alkyl methacrylate, isobornylmethacrylate,isobornylacrylate, cyclopentylmethacrylate, cyclopentylacrylate,cyclohexylmethacrylate, cyclohexylacrylate, styrene,2,4,6-trimethylstyrene (TMS), and t-butyl styrene (TBS), andcombinations thereof.
 10. The method according to claim 8, wherein thelens-forming composition comprises an organic solvent.
 11. The methodaccording to claim 8, wherein the total amount of allsilicone-containing polymerizable components present in the lens-formingcomposition is about 65% or less.
 12. The method according to claim 11,wherein the hydrophilic vinylic monomer is a hydrophilic N-vinylmonomer.
 13. The method according to claim 12, wherein the lens-formingcomposition further comprises a non-silicone vinylic crosslinkerselected from the group consisting of ethyleneglycol di-(meth)acrylate,diethyleneglycol di-(meth)acrylate, triethyleneglycol di-(meth)acrylate,tetraethyleneglycol di-(meth)acrylate, glycerol di-(meth)acrylate,1,3-propanediol di-(meth)acrylate, 1,3-butanediol di-(meth)acrylate,1,4-butanediol di-(meth)acrylate, glycerol 1,3-diglycerolatedi-(meth)acrylate, ethylenebis[oxy(2-hydroxypropane-1,3-diyl)]di-(meth)acrylate, bis[2-(meth)acryloxyethyl] phosphate,trimethylolpropane di-(meth)acrylate, and3,4-bis[(meth)acryloyl]tetrahydrofuan, diacrylamide (i.e.,N-(1-oxo-2-propenyl)-2-propenamide), dimethacrylamide (i.e.,N-(1-oxo-2-methyl-2-propenyl)-2-methyl-2-propenamide),N,N-di(meth)acryloyl-N-methylamine, N,N-di(meth)acryloyl-N-ethylamine,N,N′-methylene bis(meth)acrylamide, N,N′-ethylene bis(meth)acrylamide,N,N′-dihydroxyethylene bis(meth)acrylamide, N,N′-propylenebis(meth)acrylamide, N,N′-2-hydroxypropylene bis(meth)acrylamide,N,N′-2,3-dihydroxybutylene bis(meth)acrylamide,1,3-bis(meth)acrylamidepropane-2-yl dihydrogen phosphate (i.e.,N,N′-2-phosphonyloxypropylene bis(meth)acrylamide), piperazinediacrylamide (or 1,4-bis(meth)acryloyl piperazine), vinyl methacrylate,allylmethacrylate, allylacrylate, N-allyl-methacrylamide,N-allyl-acrylamide, tetraethyleneglycol divinyl ether, triethyleneglycoldivinyl ether, diethyleneglycol divinyl ether, ethyleneglycol divinylether, triallyl isocyanurate, triallyl cyanurate, trimethylopropane trimethacrylate, pentaerythritol tetramethacrylate, bisphenol Adimethacrylate, combinations thereof.
 14. The method according to claim13, wherein the step of curing is carried out thermally.
 15. The methodaccording to claim 14, wherein the lens-forming composition is clear atroom temperature and at a temperature of from about 0 to about 4° C. 16.The method according to claim 11, wherein the siloxane-containingvinylic monomer is3-(meth)acryloxy-2-hydroxypropyloxy)propylbis(trimethylsiloxy)methylsilane,3-(meth)acryloxyethoxypropyloxypropylbis(trimethylsiloxy)methylsilane,3-(meth)acrylamidopropyl-bis(trimethylsiloxy)methylsilane, 3-N-methyl(meth)acrylamidopropylbis(trimethylsiloxy) methylsilane,mono-(meth)acryloxy-terminated polydimethylsiloxanes of variousmolecular weight, mono-(meth)acrylamido-terminated polydimethylsiloxanesof various molecular weight, or a combination thereof.